Place the thinly sliced beef in a bowl. Add olive oil, soy sauce, Worcestershire, garlic powder, black pepper, and salt. Toss to coat evenly. Let sit at room temperature for 10–15 minutes (or cover and refrigerate up to 2 hours).

cook beef

Heat a large heavy skillet or cast-iron pan over medium-high heat until hot. Add a thin film of neutral oil if pan is dry. Add the marinated beef in an even layer (work in batches if necessary to avoid crowding). Cook, stirring and breaking up slices, until browned and just cooked through, about 3–5 minutes. Remove beef to a plate and keep warm.

Vegetables

sauté peppers and onions

Reduce heat to medium. In the same skillet, add 1 tablespoon butter. Add the sliced green peppers and onions. Season with 1/4 tsp salt and 1/4 tsp black pepper. Cook, stirring occasionally, until softened and caramelized at the edges, about 7–9 minutes. Stir in the banana peppers for the last 1–2 minutes to heat through. Push vegetables to the side or transfer to the plate with the beef.

Peppercorn Mayo Sauce

make sauce

In a small bowl, whisk together the mayonnaise, prepared peppercorn sauce or cracked black pepper, lemon juice, Dijon, and 1/8 tsp salt until smooth. Taste and adjust seasoning. Refrigerate until assembly.

Assembly & Melt

toast rolls

Heat a clean skillet or griddle over medium. Butter the cut sides of the hoagie rolls. Place them cut-side down in the pan and toast until golden, about 1–2 minutes. Remove and keep warm.

combine and melt

Return the cooked beef and vegetables to the skillet and mix to combine over medium-low heat. Divide the mixture into two portions on the pan. Top each portion with two slices of provolone, cover the pan with a lid for 1–2 minutes until the cheese melts. Alternatively, spoon the meat mixture into the toasted rolls and top with provolone, then place under a broiler for 30–60 seconds to melt.

Finish & Serve

Spread about 1 tablespoon of the peppercorn mayo sauce on the cut sides of each toasted roll. Using a spatula, transfer each cheesy beef and pepper mixture into a roll. Add any extra banana peppers if desired and sprinkle with chopped parsley. Serve immediately.